Method for drying a fibrous web in a drying device, and drying device

ABSTRACT

A method for drying a fibrous web in a drying device and to a corresponding drying device is provided, in which the fibrous web is guided in an open draw with multiple deflections through the drying device through a plurality of intermediate drying spaces which are arranged parallel to one another and define web-guiding path sections, and is loaded on both sides with a drying medium, in particular hot air, for thermal transfer. The fibrous web is guided through the drying device alternately in the vertical direction in and counter to the direction of and gravity, and vice versa.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of PCT application No. PCT/EP2012/055483,entitled “METHOD FOR DRYING A FIBROUS WEB IN A DRYING DEVICE, AND DRYINGDEVICE”, filed Mar. 28, 2012, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device and a method for drying afibrous web.

2. Description of the Related Art

Generic drying devices which operate according to the impingementprinciple with hot air are already known in the state of the art invarious arrangements in the embodiment of horizontal-air drying devices.In these devices the fibrous web which is to be dried is guided throughthe drying device through drying spaces which are arranged horizontallyaligned and arranged in a vertical direction on top of one another. Thefibrous web runs through the individual drying spaces consecutivelyhorizontally from the infeed side of the drying device to the outfeedside, whereby the redirection of the fibrous web occurs through reversalbetween two drying spaces which are arranged above one another, with theassistance of turn rollers which are arranged on the infeed side and theoutfeed side. The drying spaces are hereby defined by blower deviceswhich are arranged on both sides of and at a distance from thetheoretical web guidance path of the fibrous web. The fibrous web istreated on both sides with hot air in the drying spaces. The hot airsupplied for this purpose by the blower devices serves as a heattransfer to the fibrous web. Due to the long web guidance path segmentsin the horizontal direction in such drying devices, it is necessary—inorder to avoid excessive stress in the gravitational direction betweenthe turn rollers which are arranged on both sides of a drying space—tosupport the fibrous web in this region by means of an air cushion.Stable operating conditions for the horizontal pass through the dryingspaces can hereby only be ensured through low flow speeds of the dryingmedium which is to be applied, through special geometries of thedischarge openings, in particular in the blower devices arranged belowand acting upon the fibrous web, as well as through different distancesbetween the discharge openings of the blower devices arranged above andbelow an individual web guidance path segment, or respectively thefibrous web. Since the blower device arranged below a web guidance pathsegment serves to form the necessary air cushion, the design, inparticular the geometry, of the discharge openings of the blower device,their configuration and operational parameters, as well as theoperational parameters and state variables of the drying medium, are tobe adapted to this function. The layout, the design and the operatingparameters of the blower device above the web guidance path segmentacting on the other side of the fibrous web is to be selected so thatthis does not affect the formation of the air cushion. The possibilityof a purposeful profiling of the drying medium to be applied onto thefibrous web side facing in the gravitational direction is not possibleunder these conditions. The greater distance of the blower devicesdisposed above a web guidance path segment impairs the heat exchange.

Due to the additionally required support for the fibrous web over eachindividual web guidance path segment a control of the drying rate overan individual web guidance path segment is not possible. Because of themulti-function of the drying medium which is applied to the fibrous web,only low drying rates are achievable.

An additional disadvantage with horizontal web guidance is that in theevent of a web break, the web can only be removed from the drying spaceswith difficulty and at great expense. Special devices are herebyrequired to avoid contamination of the individual blower devices as wellas for their protection, for example in the form of grating.

Another drying device operating according to the impingement principlewith hot air and with vertical fibrous web guidance which is arrangeddownstream of a pulp press is known from publication DE 699 09 999 T2.In this case however, a pulp having a very low dry content is guidedthrough the drying device, continuously supported on a fabric belt.

What is needed in the art is a more effective and efficient method fordrying a fibrous web and an associated drying device so that theaforementioned disadvantages are avoided. In particular, a drying deviceis needed in the art which is characterized by simple fibrous webguidance and at the same time easily realizable activecontrol/adjustment of the drying rate along the web path, as well as ahigh drying rate in a small space. The individual drying spaces shouldbe easily accessible and the fibrous web should be easily removable fromthem in the event of a web break. The engineering effort should be keptlow.

SUMMARY OF THE INVENTION

The present invention provides a device and a method for drying afibrous web which allows for control/adjustment of the drying rate alongthe web path and easy removal from individual drying spaces in the eventof a web break. According to the present invention, the fibrous web isguided in an open draw with multiple redirection through the dryingdevice, through a plurality of drying spaces which are arranged parallelto each other and represent web guiding path sections. The web istreated on both sides with a drying medium, for example hot air for heattransfer. More specifically, the present invention provides a method fordrying a fibrous web in a drying device wherein the fibrous web isguided in an open draw without being supported by clothing, withmultiple redirection through the drying device through a plurality ofdrying spaces which are arranged parallel to each other and representweb guiding path sections. The web is treated on both sides with adrying medium, for example hot air for heat transfer. The fibrous web isguided through the drying device alternately in a vertical direction andopposite to the direction of gravity, and vice versa. Guidance of thefibrous web through the drying device occurs therefore alternatelyunsupported by clothing from the bottom up and from the top down, orvice versa.

The fibrous web is guided over guiding devices, such as turn rollers,for example through a plurality of drying spaces arranged parallel toeach other and extending in a width direction of the drying device andin a vertical direction, and at the transition between two adjacentdrying spaces. The individual drying space is hereby defined by blowerdevices arranged on both sides of the web guidance path and eachrepresenting one blower unit.

The vertical direction is consistent with the direction extendingsubstantially perpendicular to a horizontal reference plane.Substantially in the vertical direction means that also deviations, thatis variances in the range of approximately ±20° of the web path from thevertical direction are still possible and are included in this term. Thehorizontal reference plane may, for example, be described by a floor,machine floor or a base.

A web guidance path segment is to be understood to be the web pathsegment theoretically characterized by the guidance of the fibrous web.The individual vertically aligned web guidance path segment intended forguidance of the fibrous web is defined by the arrangement of theindividual turn rollers which are allocated to the respective dryingspace for transferring into/transferring out of the respective adjacentdrying space.

The vertical guidance of the fibrous web offers the advantage that thefibrous web, in the event of a breakdown or web break, can be removedfrom the individual drying space quickly and at the lowest possibleexpense, in particular since it can continue to run in the direction ofgravity in catch- and/or processing devices located below the individualdrying spaces.

Due to the multiple returns, very long web guidance paths are realizablein the drying device. The individual web guidance path segmentsextending in the vertical direction can be realized by utilizing theoverall height that is theoretically available for the drying device,thereby being able to provide high drying efficiencies in a machinedirection, in other words viewed in a longitudinal direction of thedrying device within a minimal construction space.

The solution according to the present invention moreover offers theadvantage of a simple and targeted treatment of the fibrous web withdrying medium, since this is no longer required for stabilizing thefibrous web when guiding it through the drying device, but has only toassume the task of the heat transfer.

By eliminating the dual function of the drying medium, the individualblower devices can be arranged at small distances from the web guidancepath segment and thereby from the fibrous web, thereby improvingefficiency. Higher flow velocities and thereby higher drying rates arepossible.

The dry content of the fibrous web at the infeed to the drying device isthereby at least approximately 45%, for example 50%.

In accordance with one arrangement of the device according to thepresent invention, the individual sides of the fibrous web, at least ina region of a web guidance path segment inside an individual dryingspace are treated equally with drying medium. This means that thefibrous web in this web guidance path segment is treated equally on bothfibrous web sides. The individual operating parameters of the blowerdevices which are arranged on both sides of the fibrous web and statevariables of the drying medium emerging from the blower devices areequal in this region. This improves the uniformity of the fibrous web.

In order to influence the dry profile of the fibrous web, the individualfibrous web sides, at least in one region of a web guidance path segmentinside an individual drying space, can also be treated differently withdrying medium. This option allows possibly for example upstreamone-sided or different two-sided treatment of the fibrous web prior torunning into the drying device.

In accordance with one embodiment of the present invention, treatment ofone fibrous web side can be profiled in an individual drying space in awidth direction of the drying device and/or over the entire extension ofthe drying space in a vertical direction, and can be controlled and/orregulated incrementally or infinitely, for example in one or in aplurality of zones. The advantage exists in the possible profiling ofthe drying efficiency and thereby the drying rate in the differentdirections of the fibrous web and thereby in the ability to influencethe characteristics of the fibrous web which are subject to drying. Thisallows uniform drying over the entire fibrous web width while avoidingexcessive drying of the edge regions. Moreover, changing edge conditionscan be can be locally targeted in a timely fashion. The presentinvention, by its configuration, permits optimization of the dryingprocess in all regions of an individual web guidance path segment.

A uniform treatment of a fibrous web side in an individual drying spacein the width direction and over the entire extension of the drying spacein the vertical direction is also conceivable.

Profiling occurs depending on at least one of the following parametersdefining the operational mode and/or geometry of an individual blowerdevice and/or state variable of the drying medium and/or parameters ofthe fibrous web:

-   -   a variable characterizing the geometry of the discharge opening        from the blower device;    -   discharge angle of the drying medium+45°;    -   flow speed of the drying medium, for example 5 meters per second        (m/sec) to 60 msec;    -   volume flow of the drying medium, for example 3 cubic meters per        minute per blower device (m³/min/m/blower device) to 20        m³/min/m/blower device;    -   distance of the blower device to the fibrous web, for example 5        millimeters (mm) to 50 mm;    -   state variables of the drying medium (temperature, pressure),        for example a temperature in the range between approximately        100° C. and 350° C. and/or a pressure between approximately 400        Pascal (pcal) to 2000 pcal;    -   throughput per time unit; and    -   speed of fibrous web, for example 50 meters per minute (m/min)        to 350 m/min.

In order to avoid fibrous web breaks an additional arrangement of thepresent invention provides that a plurality of drying spaces which arearranged parallel to each other and extend in a cross direction and avertical direction of the drying device, the turn rollers coupling themand thereby the web guidance path segments defined by them are combinedinto a group. Several groups, however at least two, may be provided in adrying device. The individual groups are arranged and formed such thatthe extension of the web guidance path segments progressing through theindividual drying spaces viewed in the vertical direction from an infeedinto the drying device to the outfeed from the drying device increasesin size from group to group. In consideration of the formation and theoperating parameters of the drying device, the group having the maximumextension is arranged such that it is reached only when a predeterminedminimum dry-content of the fibrous web is achieved. This is the drycontent which is necessary to be able to let the fibrous web hang freelyover the maximum span of the web guidance path, without it tearing. Thedry content of the fibrous web in the region of the infeed into thedrying device is, for example between 45% and 50%, and on the outfeedside approximately 90%, whereby at least one drying curve is providedbetween the two.

An additional arrangement of the present invention provides that alwaysa plurality of drying spaces which are arranged parallel to each otherand extend in the cross direction and the vertical direction of thedrying device, and the turn rollers coupling them are combined into agroup, whereby the individual groups are arranged and formed such thatthe speed of the fibrous web in the individual groups can be controlledseparately. This offers the advantage of an individual adjustment of thetension of the fibrous web and thereby the stress upon it.

Advantageously the supply of the individual blower devices occursthrough a drying medium supply system which is allocated to at least oneindividual blower device and can be connected with same. According to afurther embodiment of the present invention, the moist drying mediumwhich is present after the drying process in the individual drying spaceis processed and is again supplied as drying medium via the blowerdevices to the drying space. For this purpose, the drying medium whichis to be supplied to a drying space and the drying medium enriched withmoisture from the drying space is led between two adjacent blowerdevices of one or different blower units in a loop with optional in-linewarming—or for example, heating devices. This is realized throughrecirculating blowers which are arranged on both sides of a blower unitand which are connected with the suction side with the dryer space andwith the pressure side with a blower device. Separate suction devices inthe region of the individual drying space can thereby be eliminated.

In order to improve access to the drying spaces for the purpose ofmaintenance and cleaning, the width of the individual drying space isvariably adjustable in the machine direction. In the event of a webbreak the fibrous web can thereby be quickly and securely guided intocatch—and processing devices which are arranged below the drying device.

In order to ensure a safe web removal in the event of a web break orother malfunction, the fibrous web is severed consecutively orsimultaneously between the individual web guidance path segments in theindividual drying spaces. The separation occurs, for example in thereturn region between to drying spaces which are arranged following eachother in the direction of web travel.

According to the present invention, the drying device for drying afibrous web, including blower devices arranged on both sides of thetheoretical web guidance path for the application of drying medium ontothe fibrous web which is guided in the drying space formed by themfurther provides the individual blower devices are arranged extending inthe cross direction of the drying device and extending in the verticaldirection. The drying spaces progressing in the vertical direction arelimited. A plurality of drying spaces progressing in the verticaldirection are arranged adjacent to each other to accommodate webguidance path segments in the machine direction and above and below anindividual drying space, turn rollers are provided for transferring thefibrous web between two adjacent drying spaces. Two turn rollersallocated to a drying space for connection with the adjacent dryingspace define web guidance path segments. The drying device is free of afibrous web supporting clothing.

The repeated reversal allows very long web guidance paths inside thedrying device. The thereby formed individual web guidance path extendingin the vertical direction can be realized by utilizing the overallheight that is theoretically available for the drying device, therebyrealizing the high efficiencies in the machine direction, in other wordsviewed in the longitudinal direction of the drying device within aminimal construction space. Apart from the redirection, the fibrous webis guided essentially only in the vertical direction and is stabilizedthrough gravitational force. This allows for a targeted local and timelytreatment of the fibrous web with drying medium, since this is its mainfunction and only needs to serve to heat the fibrous web and is notrequired for formation of stabilizing air cushions. By eliminating thedual function of the drying medium, the individual blower devices can bearranged at small distances from the web guidance path segment andthereby from the fibrous web, thereby improving efficiency.

In accordance with one embodiment of the present invention theindividual blower devices which are always arranged on both sides of anindividual web guidance path segment represent one blower unit. Theindividual blower device can be arranged to be subdivided into blowerzones in the cross direction and/or in the vertical direction of thedrying device, whereby a device or controller for individual and/orjoint control of the individual zones is provided.

The individual blower device includes, for example, a plurality of blowboxes arranged in the vertical direction in blower towers which arearranged extending in the cross direction of the drying device and whichare supported on a frame.

A drying medium supply system is allocated to the individual blowerdevice alone or to several together which, in the simplest case,includes a drying medium supply unit coupled with the blower device. Inone arrangement according to the present invention, viewed in the crossdirection of the drying device, recirculating blowers are arranged onboth sides of the individual blower unit, whose suction sides areconnected with the drying space and pressure sides with a blower deviceof the blower unit, forming a circulation system, whereby upstream fromthe connection of the pressure side with the blower device a heatingdevice for heating of the drying medium which is to be brought into theblower device can be located. In a further development, therecirculating blowers allocated to a blower device are advantageouslyarranged in the vertical direction one above the other and supported ina blower tower. This can be constructed separately or as a component ofthe frame. The blower tower can be constructed so that it can be movedaway from the drying device.

In an additional embodiment of the present invention, the drying mediumsupply system includes at least one fresh air supply and at least oneexhaust air removal which can be connected with one and/or a pluralityof loops. Fresh air supply and exhaust air removal have no fluidicconnection with each other, but can however be optionally coupledthermally in an advantageous manner, for example through a heatexchanger. The heat of the exhaust air can thereby be purposefully andeffectively used for heating the supply air to the blower devices.

To ensure a secure operation, a plurality of drying spaces arrangedparallel to each other and extending in the cross direction and in thevertical direction of the drying device and the turn rollers connectingthem with each other form a group. At least two groups are providedinside the drying device. The individual groups are arranged and formedsuch that the extension of the web guidance path segments progressingthrough the individual drying spaces viewed in the vertical directionfrom an infeed into the drying device to the outfeed from the dryingdevice increases in size from group to group.

In an alternative or additional embodiment of the present invention, adevice or controller for controlling the speed of the fibrous web, forexample the rotational speed of the turn rollers is allocated to atleast one individual group for adjusting the web tension.

To improve removal of fibrous web residues after a web break and for thepurpose of cleaning, an apparatus or device for adjusting the width ofat least one single drying space in the machine direction is provided.This device can include a mechanism for sliding and/or pivoting or acombination of both movements of the blower device. In one arrangementof the present invention, the device includes rotatable mounting unitsfor two adjacently located blower devices of different blower units. Theindividual mounting unit includes a rocker arm rotatably mounted on theframe of the drying device on opposite ends of which the blower devicesare flexibly hinged. Pivoting occurs through engagement of an adjustingdevice on a force application surface on the rocker arm. In accordancewith one embodiment of the present invention, the activation of aplurality of mounting units can occur forcibly coupled.

In a further embodiment of the present invention, at least one knock-offdevice is provided which—in the event of malfunctions—severs the fibrousweb in the region between two drying spaces, as a result of which theremainder of the fibrous web falls in the direction of gravity. Ifseveral knock-off devices are provided, these can become effectivesimultaneously or consecutively between two drying spaces.

The arrangement of the effective region of individual knock-off devicescan occur according to one of the following options:

-   -   in the vertical direction in the region of the upper turn        devices;    -   in the vertical direction in the region of the lower turn        devices; or    -   inside the drying spaces, for example in the vertical direction        between upper and lower turn devices.

The individual knock-off device can be configured or arranged so thatits effective region is such that it extends at least over a section ofthe drying device in the cross machine direction or is movable, wherebythis section can be constantly predetermined or adjustable. In thiscase, the fibrous web is only partially severed, whereby the remainingfibrous web due to the weight of it tears in the gravitationaldirection.

In one embodiment of the present invention, the individual knock-offdevice is configured or can be arranged so that its effective region issuch that it extends at least over the extension of the fibrous web inthe cross machine direction, for example the extension of the dryingdevice in the cross machine direction.

Regarding the configuration and mounting of the individual knock-offdevice, there are a multitude of options. The individual knock-offdevice includes at least one knock-off element which is mounted on astationary or movable support. In the latter instance, the support canbe movable, for example sliding in the vertical direction and/or themachine direction and/or the cross machine direction. Moreover, inaddition or alternatively to the aforementioned option, the support canbe pivoted. Mounting on the support depends on the selection of the typeof knock-off element and the form of the movability of the support. Inthe case of a movable support, the knock-off element may also be mountedstationary on it.

On a stationary or movable support the individual knock-off element canbe mounted on it movably in the cross machine direction, and in contrastto this possibly also pivoted.

The inventive solution is suitable, for example for drying of fibrouswebs consisting of cellulose fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a schematically simplified illustration which clarifies thebasic configuration and basic function of a drying device according tothe present invention;

FIG. 2 is detail of a section from a web guidance path segment accordingto the device of FIG. 1;

FIGS. 3A to 3F illustrate different modification options for anindividual blowing device in the device according to the presentinvention;

FIG. 4 is an exemplary illustration of fibrous web guidance in a dryingdevice with group sectioning according to the present invention;

FIG. 5 is an exemplary illustration of drying medium guidance forindividual blower units in the device according to the presentinvention;

FIG. 6 is a schematically simplified perspective illustration of ablower tower of the device according to the present invention;

FIG. 7 illustrates the fresh air supply and exhaust air removal in thedevice according to the present invention;

FIG. 8 illustrates a possible configuration of a frame for a dryingdevice according to the present invention;

FIG. 9 is an exemplary illustration of a possible configuration of aplatform component of the frame of the device according to the presentinvention;

FIGS. 10A to 10C illustrate an inventive option for variable adjustmentof the width of the drying space between two blower devices of a blowerunit of the device according to the present invention;

FIG. 11 illustrates a possible arrangement of grating of the deviceaccording to the present invention;

FIG. 12 illustrates an embodiment of an inventive drying device withadditional knock-off device; and

FIGS. 13A to 13E illustrate possible function positions of the knock-offdevices of the device according to the present invention.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate one embodiments of the invention and such exemplificationsare not to be construed as limiting the scope of the invention in anymanner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there isschematically illustrated, in a greatly simplified depiction, the basicconfiguration and basic function of a drying device 1 according to thepresent invention. For visualization of individual directionalstatements a coordination system has been established. X-direction isconsistent with the direction of travel of fibrous web F through dryingdevice 1. This is consistent with the longitudinal direction of dryingdevice 1 and is therefore also identified as machine direction MD.Y-direction describes the direction perpendicular to machine directionMD, that is width direction of device 1 and is identified as crossmachine direction CD. Z-direction is the height direction, that is theextension in the vertical direction.

According to the present invention, drying device 1 is a vertical dryingdevice according to the impingement principle. Fibrous web F is guidedthrough drying device 1 in an open web draw and with severalredirections, in other words repeated directional changes, between aninfeed 4 into drying device 1 and an outfeed 5 from drying device 1,essentially only in the vertical direction. Deviations of +20° from thevertical direction are possible. Drying device 1 is in the embodiment ofa blower device, or respectively air drying device. Along its webguidance path, fibrous web F is treated on both sides with dryingmedium, for example with hot air. In contrast to the horizontal airdrying devices known from the current state of the art, the hot airacting upon fibrous web F in the inventive solution, serves primarilyonly to transfer heat to fibrous web F and due to the vertical guidanceof fibrous web F is not necessary for stabilization of the guidance offibrous web F.

The application of the drying medium occurs by blower devices 2.na and2.nb with n≧1 which are arranged on both sides of fibrous web F alongthe web guidance path, at a distance to same and thereby effective ondifferent fibrous web sides. Blower devices 2.na and 2.nb which arearranged on both sides of fibrous web F along a web guidance pathsegment form a blower unit 2.n with n≧1. The individual blower devices2.na and 2.nb, in this case 2.1 a to 2.na and 2.1 b to 2.nb are arrangedin such a way that the blower devices 2.na, 2.nb of always one blowerunit 2.n limit a drying space 3.n progressing in the vertical direction,with n≧1. Viewed in machine direction MD, blower units 2.1 to 2.n withblower devices 2.1 to 2.na and 2.1 b to 2.nb limit here a plurality ofdrying spaces 3.1 to 3.n progressing in the vertical direction. Theseare arranged parallel to each other in machine direction MD and adjacentto each other. Guidance of fibrous web F occurs herein in the verticaldirection—in other words from top to bottom or vice versa. Drying spaces3.1 to 3.n accommodate hereby the vertically progressing web guidancepath segments. The web guidance between two adjacent drying spaces 3.n-1and 3.n occurs through turn rollers 6, 7.

The web guidance path of fibrous web F thereby includes a plurality ofweb guidance path segments, arranged parallel to each other andprogressing in the vertical direction which are coupled together viaturn rollers 6 and 7 and are arranged inside drying spaces 3.n.

Referring now to FIG. 2, there is shown an exemplary illustration of asegment from the web guidance path in drying space 3.1 formed by blowerunit 2.1 for fibrous web F which is to be dried in drying device 1according to FIG. 1. Individual blower devices 2.1 a and 2.1 b arearranged on both sides of the web guidance path of fibrous web F whichis guided in the vertical direction and at a distance to same andthereby in the case of fibrous web F at a distance from it. Blowerdevices 2.1 a, 2.1 b act at least indirectly upon the surface of fibrousweb F for the purpose of drying. Illustrated is the operational modewith uniform treatment of both sides of fibrous web F with hot air. Itsdischarge from individual blower devices 2.1 a and 2.1 b and impingementupon the respective fibrous web side is clarified by means of arrows.The individual jet thereby has at least one discharge angle α from therespective blower device 2.1 a, 2.1 b and an angle of impingement β ontothe surface of fibrous web F. Impingement of the hot air occurs, forexample, perpendicular to fibrous web F. In the respective impingementregion the treatment of fibrous web F can thereby be influenced andactively controlled and/or regulated as a function of at least one ofthe following state variables characterizing the geometry and/oroperational mode of blower device 2.1 a, 2.1 b:

-   -   discharge angle from the blower device;    -   impingement angle onto the fibrous web; and    -   discharge width of the discharge opening from the blower unit.

Moreover, treatment of fibrous web F with drying medium can be adjustedas a function of the state variable of the drying medium (temperature,pressure),—discharge speed and/or volume flow of drying medium from theblower device and/or the values characterizing at least indirectly theoperational mode of drying device 1, for example traveling speed offibrous web F.

For adjustment, for example control and/or regulating, a control device8 is provided. Depending on predefined set points for the dryingefficiency that is to be achieved or values characterizing same at leastindirectly, individual blower devices 2.1 a, 2.1 b to 2.na, 2.nb arecontrolled. This is clarified in an example through coupling of theoutputs of controller 8 with the control devices of blower devices 2.1a, 2.1 b by issuing the hereby necessary manipulated variables Y2.1 aand Y2.1 b for blower devices 2.1 a, 2.1 b.

FIG. 2 illustrates an arrangement with uniform treatment on both sidesof fibrous web 2 in the web guidance direction however, otherpossibilities are also conceivable which can be used by themselves or incombination with each other. Such additional developments areillustrated in FIGS. 3A to 3D.

In contrast to FIG. 2, FIG. 3 illustrates a possibility of the differenttreatment of the individual sides of fibrous web F with drying mediumwhich is indicated by arrows of different sizes. For example, the dryingmediums applied to opposite sides of the fibrous web can becharacterized by different state variables, for example differenttemperatures.

Moreover there is the possibility alternatively or in addition ofprofiling of the drying medium over a desired application region onfibrous web F. Such possibilities are shown in FIGS. 3B to 3D. In allthese possibilities the profiling can occur as a function ofcharacterizing parameters of the geometry and/or the operational mode ofblower device 2.1 a, 2.1 b and/or the speed of the fibrous web. Theprofiling can occur in the direction of web travel and/or transverselyto it.

FIG. 3B illustrates an example for blower device 2.1 a, showing thepossibility of profiling of the drying medium in the direction of travelof fibrous web F through drying device 1, in particular over a webguidance path segment in drying space 3.1. Differently sized arrowsshown the change in the drying medium profile in the direction of travelof fibrous web F inside drying space 3.1

FIG. 3C is a schematically simplified illustration showing the possiblearrangement of blower device 2.1 with blower zones sectioned in thevertical direction. The individual zones are for example identified withBZ1 to BZn. These can be realized in one single blower device 2.1 a bysubdividing a common interior space into individual partial spaces, orby arranging blower device 2.1 a with individual separate blowerdevices, for example blow boxes. A desired dry medium distributionhaving the desired characteristics can be achieved over the web guidancepath segment in dryer space 3.1 through the individual and/or groupcontrol of the individual zones.

In a section from a view onto blower device 2.1 a in the CD/z-plane,FIG. 3D illustrates an additional development of one arrangement fromFIG. 3C, whereby blower zones are divided in addition also in the widthdirection of drying device 1. The individual zones are identified, forexample, with BZ1.1 to BZ1.n to BZn.1 to BZn.n with n>1. These can berealized in one single blower device 2.1 a by subdividing a commoninterior space into individual partial spaces and/or by arranging blowerdevice 2.1 a with individual separate blower devices, for example blowboxes. A desired drying medium distribution having the desiredcharacteristics can be achieved over the web guidance path segment indryer space 3.1 and moreover in cross machine direction CD—that is thewidth direction—through the individual and/or group control of theindividual zones. The arrangement of individual blower device 2.1 isalso conceivable consisting of a plurality of blowers that are arrangedone above the other in the vertical direction and extending at leastover the width of fibrous web F which is to be conditioned in dryingdevice 1, whereby the individual blowers describe blower zones in thevertical direction and are moreover sectioned/divided into zones in thecross machine direction. Control of individual zones BZ1.1 to BZn.noccurs in this case also individually, in groups or together.

The size of the zone can be constant or can vary in cross machinedirection CD and/or in vertical direction.

In all embodiments of the present invention, the treatment of fibrousweb F with drying medium can occur selectively, linearly or over anarea. An area treatment covering the entirety of the fibrous web isstrived for. The drying medium can hereby be applied by blower device2.1 a through a plurality of individual nozzles 9.1 to 9.n having around cross section as shown in FIG. 3E in an exemplary view of asection from blower device 2.1 a. Use of other cross sectionalgeometries is also conceivable, such as slotted nozzles 10.1 to 10.nextending at least over a partial region of the extension of blowerdevice 2.1 a in cross machine direction CD, as illustrated in FIG. 3F inan exemplary view onto a section of a blower device 2.1 a.

A further development of the present invention provides that insideindividual drying spaces 3.1 and 3.n, grating is to be provided on theblower devices in front of the outlet openings for the drying medium toprotect them from contamination from fibrous web F in the event of a webbreak.

Referring now to FIG. 4, there is shown a greatly simplified schematicillustration of a view in the machine direction MD/z-plane onto dryingdevice 1, clarifying an exemplary possible guidance of fibrous web F,without illustration of the blower devices. Fibrous web F is illustratedhere in broken lines. It is brought into drying device 1 in infeedregion 4. In the illustrated example, infeed region 4 is arranged in thevertical direction in the upper region of drying device 1. Through theindividual turn rollers 6, 7 which are arranged in the verticaldirection in rows offset to one another, fibrous web F experiences acorresponding directional change and redirection in guidance in thevertical direction through drying device 1 through to outfeed 5 which isarranged, for example in the vertical direction, in the lower region ofdrying device 1. It can be seen here that fibrous web F experiences amultitude of directional changes and, viewed in machine direction MD isthereby guided in the most confined space over a plurality of parallelweb guidance path segments. Due to this, the dwell time inside dryingdevice 1 can be considerably increased. FIG. 4 does not illustrateindividual blower devices 2.1 a, 2.1 b to 2.na, 2.nb which are arrangedon both sides of the web guidance path resulting from the guidance offibrous web F and which form or respectively limit drying spaces 3.1 to3.n.

It can be seen that fibrous web F is not immediately guided in thevertical direction through drying device 1 utilizing the maximumpossible height of same. The web guidance path segments following infeedregion 4 are characterized by a smaller extension in the verticaldirection and thereby height than the following web guidance pathsegments. This is recognized on the different vertical offset of turnrollers 6 and 7 which characterize a web guidance segment and which arearranged above and below the individual drying space. Upper turn rollers6 are thereby arranged in the vertical direction at one level and at adistance from each other in machine direction MD, whereas lower turnrollers 7 are arranged at different height levels.

A plurality of drying spaces which are arranged parallel to each otherand extend in cross machine direction CD and in the vertical direction,and associated turn rollers 6, 7 and the thereby defined web guidancepath segments are combined into groups, in this case I to VI. Insideindividual groups I to VI the drying spaces or individual web guidancepath segments are, for example, arranged with constant extension in thevertical direction. The height of the individual drying spaces orrespectively the extension of the web guidance path segments progressingthrough them increases from group to group. Fibrous web F is therebyguided over the maximum extension of drying device 1 in the verticaldirection in group V only from the time when fibrous web F reaches apredefined dry content. The entire available space, originating fromfloor 11 is thereby, for example used.

Infeed 4 into drying device 1 can be implemented through an automatictransfer system, for example through a rope transfer.

In the region of outfeed 5 from drying device 1 a cooling region 26 maybe provided. Here, fibrous web F is treated only with ambient air whichis, for example, supplied via non-illustrated centrifugal blowers to thealso non-illustrated blower devices which are arranged along therespective web guidance path segment on both sides of fibrous web F.Cooling region 26 includes here group VI.

To supply individual blower devices 2.1 a to 2.na, 2.nb with thenecessary hot air, drying medium supply system 12 is provided. Thisincludes blowers which supply blower devices 2.1 a, 2.1 b to 2.na, 2.nbwith the required drying medium at the required process parameters.These are functionally coupled with the associated blower devices.

In order to ensure smooth operation it is moreover necessary to alsoremove the moist air from individual drying spaces 3.1 to 3.n. Blowersare also used for this. Recirculation blowers may be used which, inaddition to removal of the moist drying medium, for example moist air,also serve to blow in heated drying medium, such as air as the dryingmedium.

FIG. 5 clarifies in a schematically simplified illustration anembodiment of the drying medium guidance in a view onto the MD/CD plane,as a component of drying medium supply system 12. The drying medium isguided inside one, or through blower units 2.1 to 2.n, overlapping inloops K which are a component of drying medium supply system 12.Individual loop K is free of fresh air supply. This means that the airwhich is present in the system is guided in respective loop K and in theforward flow serves to transport heat to fibrous web F. In the returnflow the exhaust air is heated in order to bring it to a predefinedtemperature before it is again supplied to blower units 2.1 to 2.n.Recognizable are recirculation blowers 13 which are arranged on bothsides in cross machine direction CD of blower devices 2.1 a to 2.2 b ofblower units 2.1 to 2.2 and which serve to remove moist air from dryingspaces 3.1 to 3.n and to supply dry air as the drying medium to blowerdevices 2.1 a to 2.3 b. The air flow is thereby guided in cross machinedirection CD. After, for example, hot air heat is transferred from thedrying medium to fibrous web F by at least partial evaporation the moistairflow emerges from the respective drying space 3.1 to 3.n. The dryingmedium is hereby, for example guided in a loop between individual blowerdevices 2.1 a, 2.1 b, 2.2 a, 2.2 b, whereby after exiting from these theair is guided over heating device 14 and is supplied again byrecirculating blower 13 to the blower devices located adjacent to oneanother in machine direction MD of the same or adjacent blower units 2.1to 2.n. Here too, after exiting from this respective blower device arecirculation occurs to the blower device located upstream or downstreamin the machine direction of the same or adjacent blower units. Theindividual recirculating blowers 13 required for this, as well asheating devices 14 located before the infeed into blower devices 2.1 ato 2.3 b are thereby always arranged on both sides of blower units 2.1,2.2 in so-called blower towers 27 as indicated for example in FIG. 6.Depending on the extension of an individual blower device which is ablow box in the vertical direction at least one recirculating housing isallocated to same. One or several recirculation blowers 13 can therebyby allocated to one blow box, or one recirculation blower 13 can beallocated to several blow boxes which are arranged one above the other.Individual recirculation blowers 13 are equipped with frequencyconverters for control of the operational mode. Each individual blowertower 27 is thereby allocated to one side of drying device 1 in crossmachine direction CD that is in the width direction of the web and has afluidic connection with respective blower devices 2.1 to 2.n. Blowertowers 27 include the supports for blowers 13 and always form one unitwhich can be moved away from drying device 1 if required. Individualrecirculating blowers 13 and heating devices 14 located downstream fromthem may be arranged so that easy accessibility is provided. They may bearranged in different levels and are accessible to maintenance andinspection personnel in each level through inspection doors 19. Theblower devices are also arranged as blower devices 2.1 a to 2.nextending in the vertical direction always over the height of one leveland in cross machine direction CD extending over same. The level-typearrangement is especially advantageous. Other configurations are howeveralso conceivable. However, at least one or several recirculating blowersor recirculating motors 13 should be accessible on each level.

The supply of fresh air through drying medium supply system 12 isillustrated in a schematically simplified depiction with a view ontoCD/Z plane of drying device 1 in FIG. 7. Whereas loops K are guided incross machine direction CD, the fresh air supply occurs in respect tothe flow direction at an angle, in this case perpendicular to airguidance in loops K. FIG. 7 shows exhaust removal 28 and fresh airsupply 29. There is no fluidic connection between them, meaning thatthere is no intermixture of exhaust air AL and supply air ZL, orrespectively fresh air. Exhaust air AL is removed in the verticaldirection on top from the individual blower units 2.1 to 2.n, in otherwords from above the last blower device, for example the last row ofblow boxes in an individual blower unit 2.1 to 2.n, whereas supply airZL is supplied from below to individual blower units 2.1 to 2.n in thevertical direction to the lower rows of blow boxes. The supply occurshereby on both sides of drying device 1, for example through blowertowers 27.

For this purpose they are equipped with at least one supply opening inthe lower region, for example on the floor of the first level, and withat least one discharge opening in the vertical direction in the upperregion, for example an upper corner or a side wall of the upper level ofblower tower 27. Exhaust air removal 28 and fresh air supply 29 arehowever coupled energetically, for example thermally in order to utilizethe heat contained in the exhaust air AL to preheat supply air ZL. Thecoupling occurs, for example, through at least one heat exchanger 30which can be in different embodiments and through which the two mediumsare guided in parallel flow or counter flow. In the simplest case,exhaust air AL is guided around a wall section in the path for supplyair ZL.

Constructively, individual turn rollers 6, 7 and blower devices 2.1 a,2.1 b to 2.na, 2.nb of individual blower units 2.1 to 2.n and/orrecirculating blowers 13 and heating devices 14 or respectively blowertowers 27 respectively are supported on frame 15, an example of which isillustrated in FIG. 8. As already explained, individual blower devices2.1 a to 2.nb are always arranged in blower towers in which in thevertical direction blow boxes extending across the machine width arearranged one on top of another. Frame 15 forms a support structure forthem consisting of support members. The support structure defines spaces16 arranged parallel to each other in machine direction MD and extendingin the vertical direction, to accommodate individual blower units 2.1 to2.n. Platforms are located on both sides of spaces 16 in cross machinedirection CD to ensure accessibility to the drying spaces. Theindividual platforms on the operating and drive side of drying device 1are always combined in one platform component 17 and are anchored in thebasic structure of the frame. To protect operating personnel and toensure accessibility to blower devices 2.1 a to 2.nb, as well as todrying spaces 3.1 to 3.n for the purpose of cleaning and inspection,respective platform component 17 is equipped with appropriate panels 18and shutters or door parts 19 as illustrated in FIG. 9. Recirculatingblowers 13 and heating devices 14 can thereby be mounted directly inframe 15.

In this case, individual blower tower 27 consists of these and framecomponents of frame 15. The support structure for recirculating blower13 and heating device 14 is however, for example, provided by a separateframe component 31, as illustrated in FIG. 6, which is connected orrespectively can be combined to a detachable constructional unit withframe 15.

FIGS. 10A to 10C illustrate an embodiment of drying device 1 withpossibility of at least a temporary enlargement of individual dryingspaces 3.1 to 3.n. Individual blower devices 2.1 a, 2.1 b to 2.na, 2.nbare supported in frame 15 in a manner that drying space 3.1 to 3.nformed between them can be varied in regard to its extension in machinedirection MD. This is achieved through mounting unit 20. This includes arocker arm 21 which is rotatably mounted on frame 15 by a swivel joint22 on which two blower devices which are located adjacent to each otherfrom one or from two different blower units are flexibly hingedrespectively at a distance (a) from the pivot point. Distance (a) fromthe pivot point is, for example, selected to be the same for both blowerdevices. In an arrangement of the present invention, the adjacentlylocated blower devices of different blower units 2.1 to 2.n are mountedon rocker arm 21. In FIG. 10A blower devices 2.1 b and 2.2 a, 2.2 b and2.3 b, 2.3 b and 2.4 a, 2.4 b and 2.na respectively are flexibly hingedon rocker arm 21 at a distance to its pivot point. Mounting can occurdepending on the configuration of rocker arm 21 with an additionaloffset in the vertical direction to the pivot point, or free of this. Inthe first case which is illustrated in an enlargement in FIG. 10B,rocker arm 21 is triangular or trapezoid. To operate it, a forceapplication surface 25 is provided on which for example acylinder-/piston unit acts for the purpose of displacement/rocking. Therocking motion then leads to a superimposed horizontal and verticalmovement in opposite direction of blower devices 2.1 b and 2.2 a, 2.2 band 2.3 a, 2.3 b and 2.4 a and 2.na of two adjacently arranged blowerunits 2.1 to 2.n which are mounted through joints 23, 24 on rocker arm21, thus leading to a reduction in the distance to each other, wherebydrying spaces 3.1 to 3.n on the other side are enlarged.

The configuration of mounting unit 20 is shown exemplary in detail inFIG. 10B.

FIG. 10A illustrates drying device 1 under normal operational conditionwithout enlargement of drying spaces 3.1 to 3.n. FIG. 10C in contrastillustrates drying device 1 with enlarged drying spaces 3.1 to 3.n dueto tilting of individual blower devices 2.1 b and 2.2 a, 2.2 b and 2.3a, 2.3 b and 2.4 a, 2.4 b and 2.na and thereby the blower towers for thepurpose of carrying out cleaning procedures. One can see here themovement of the respective one blower tower upward in the verticaldirection and the movement coupled with this due to the connectionthrough rocker arm 21 of the adjacent connected blower tower downward,thus reducing the distance to each other, thereby increasing therespectively adjacent drying space. The movement may be controlled tooccur individually or in groups. The movement can be realizedmechanically, hydraulically, electrically, electronically or through acombination thereof. The movement of all blower devices 2.1 b and 2.2 a,2.2 b and 2.3 a, 2.3 b and 2.4 a, 2.4 b and 2.na may occur forciblycoupled together.

In contrast to the configuration in FIG. 10A, FIG. 10C illustratesdrying device 1 in the cleaning position with enlarged drying spaces 3.1to 3.n due to superimposed vertical and horizontal movement ofindividual blower devices 2.1 to 2.nb due to tilting. The movement ofblower device 2.nb of blower unit 2.n in the vertical direction downwardis recognizable, and the movement coupled thereto of connected blowerdevice 2.n+1a of the respectively adjacent blower unit 2.n+1 upward. Themovement may be controlled to occur individually or in groups. Themovement can be realized mechanically, hydraulically, electrically,electronically or through a combination thereof.

According to the embodiment of the present invention shown in FIG. 10Call blower units 2.1 to 2.n may be mounted so that they are operatedtogether, that is simultaneously and forcibly coupled.

According to an advantageous further development grating 35.1 a-35.nb isprovided inside individual drying spaces 3.1 and 3.n. In the examplethese are shown in FIG. 11 for blower units 2.1 to 2.n which aresupported on frame 15 by mounting units 20. In the simplest case theseare thin metal plates with openings through which drying medium isremoved after contact with fibrous web F and is recirculated in loop Kthrough the recirculating blower which is installed downstream in theflow path.

Referring now to FIG. 12, there is shown a schematically greatlysimplified illustration of a section from drying device 1 with at leastone additional device in the embodiment of a knock-off device, in thiscase two knock-off devices 32.1 and 32.2 to sever fibrous web F in theevent of a web break. Knock-off device 32.1, 32.2 can be configured indifferent ways. Individual knock-off device 32.1, 32.2 is mounted forexample on frame 15 and includes a support 33.1, 33.2 which is equippedwith knock-off elements, for example knock-off blades 34.1, 34.2.Individual knock-off devices 32.1, 32.2 are mounted movably, for examplesliding relative to turning devices 6 and become effective on fibrousweb F in this region. Individual knock-off device 32.1, 32.2 isconfigured such that it can be arranged suitably for knocking-off orsevering fibrous web F, at least over a partial region of the extensionin the cross machine direction, for example over the entire extension incross machine direction CD.

The knock-off elements, for example knock-off blades 34.1, 34.2 are forexample mounted on support 33.1, 33.2 which extends for example in crossmachine direction CD and are movable in this direction at least over apartial section of the support. Moreover, the mounting may be movablerelative to support 33.1, 33.2 perpendicular to the direction ofextension in the cross machine direction, or pivoted.

An alternative arrangement which is not illustrated here consists in theappropriate movability of support 33.1, 33.2 in the cross machinedirection.

Severing of fibrous web F occurs in the upper region of the dryingdevice, in particular in the region of upper turn rollers 6. In FIG. 12drying device 1 is illustrated in the operating position or also duringtagout. Knock-off devices 32.1 and 32.2 are in their operating positionI. In the illustrated example this operating position I which isconsistent with a position outside a knock-off position is characterizedby a positioning or respectively mounting of knock-off devices 32.1,32.2 before or after turn rollers 6, when viewed in machine directionMD. To bring them into a knock-off position, knock-off devices 32.1,32.2 are moved individually or together into the desired knock-offposition. The movement of the individual knock-off devices 32.1, 32.2can hereby be controlled separately or both are coupled, whereby themovements occur consecutively or simultaneously. The movement occursdependent on the starting position of knock-off devices 32.1, 32.2—inthe illustrated case for example through a movement of the support 33.1,33.2 in machine direction MD or in the vertical direction. Alsoconceivable is the arrangement which is not illustrated, withpositioning of knock-off devices 32.1, 32.2 in operating position FIonly in the vertical direction with offset to the actual knock-offposition. Knock-off elements 34.1, 34.2 are then brought into theknock-off position through appropriate positioning and movabilityrelative to support 33.1, 33.2, and are moved in the cross machinedirection, either through movement of the support or through movementrelative to the support when positioning the support in a stationaryposition.

FIGS. 13A to 13E illustrate possible positions of knock-off devices 32.1to 32.2 in different operating modes. FIG. 13A illustrates drying device1, whereby blower devices 2.1 to 2.nb are arranged in the cleaningposition. These and in particular also the blower towers formed by themare deflected due to enlargement of drying spaces 3.1 to 3.n. In thisoperating mode, knock-off devices 32.1 and 32.2 are still in operatingposition FI.

FIG. 13B illustrates the movement of knock-off devices 32.1, 32.2 in theevent of malfunction in operating position FI i. In this position theyact upon fibrous web F in the region of the first two turn rollers 6.Fibrous web F falls downward in drying spaces 3.1, 3.2 and can becaptured in a catch device and/or can be guided to a processing plant.Knock-off devices 32.1, 32.2 are moved into the desired knock-offposition for this purpose opposite to turn rollers 6.

FIGS. 13C to 13E illustrate additional operating positions FIII-FV ofknock-off devices 32.1, 32.2 which are characterized by the movement ofthe knock-off devices in machine direction MD, always to the next or thenext but one turn roller 6, so that fibrous web F, in the event of amalfunction, is present in individual drying spaces 3.1 to 3.nconsecutively as individual strips and in the spaces falls downward ingravitational direction. Knock-off device 32.1, 32.2 is thereby moved indrying device 1 so that it becomes effective always on the individualadjacent guidance regions. The severed web region is depicted with athicker rippled line. The respective previous position of individualknock-off devices 32.1, 32.2 is indicated by broken line. Theirmovements are indicated by arrows.

FIG. 13C shows knock-off device 32.1 moved in machine direction MDbehind knock-off device 32.2. This operating position of the twoknock-off devices 32.1, 32.2 is identified with FIII. In operatingposition FIV knock-off device 32.2 is moved behind knock-off device 32.1in machine direction MD. Operational position FV is characterized by thenew offset of knock-off device 32.1 in machine direction MD behindknock-off device 32.2. It can be seen that knock-off occurs onconsecutive web guidance path segments in the region of the turningdevices. Actuation or respectively positioning of individual knock-offdevices 32.1, 32.2 occurs alternately. Knock-off device 32.1 to 32.n canbe arranged with rotating blades or water jet. The rotating blades orthe water jet are arranged to be movable, for example, in the crossmachine direction, or in particular can slide.

FIGS. 13A to 13E illustrate an arrangement of the knock-off device in anupper knock-off position. Also conceivable is an arrangement which isnot illustrated here inside the drying spaces as well as also in theregion in vertical direction of lower turn rollers 7.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

Component identification list

-   -   1 drying device    -   2.1-2.n blower unit    -   2.1 a, 2.1 b, 2.na, 2.nb blower device    -   3.1-3.n dryer space    -   4 infeed    -   5 outfeed    -   6 turn roller    -   7 turn roller    -   8 controller    -   9.1-9.n nozzle    -   10.1-10-n slotted nozzle    -   11 floor    -   12 supply system    -   13 recirculating system    -   14 heating device    -   15 frame    -   16 space    -   17 platform component    -   18 panels    -   19 door    -   20 mounting unit    -   21 rocker arm    -   22 swivel joint    -   23 joint    -   24 joint    -   25 force application surface    -   26 cooling region    -   27 blower tower    -   28 exhaust air removal    -   29 fresh air supply    -   30 heat exchanger    -   31 frame component    -   32.1, 32.2 knock-off device    -   33.1, 33.2 support    -   34.1, 34.2 knock-off element    -   35.1 a-35.nb grating    -   BZ1-BZn zone    -   BZn.1-BZn.n zone    -   F fibrous web    -   FI, FII, FIII, FIV, FV operating positions of knock-off devices    -   MD machine direction    -   CD cross machine direction    -   K loop    -   X, Y, Z coordinates    -   Y2.1 a, Y2.1 b set point    -   I, II, III, IV, V, VI group    -   ZL supply air    -   AL exhaust air    -   α discharge angle    -   β angle of impingement

What is claimed is:
 1. A method for drying a fibrous web in a dryingdevice, the method comprising the steps of: arranging a plurality ofdrying spaces of the drying device parallel to each other, saidplurality of drying spaces including a plurality of web guiding pathsections; guiding the fibrous web in an open draw with a plurality ofredirections through the drying device through said plurality of dryingspaces, the fibrous web being guided through the drying devicealternately in a vertical direction with a deviation of up to andincluding ±20° from said vertical direction and opposite to a directionof gravity, and vice versa; and treating the fibrous web on both sideswith a drying medium.
 2. The method according to claim 1, wherein saiddrying medium is hot air for a heat transfer.
 3. The method according toclaim 1, wherein said plurality of drying spaces extend in a crossdirection of the drying device and are limited by a plurality of blowerdevices arranged on both sides of a web guidance path formed by saidplurality of web guidance path sections defining a blower unit and at atransition between two adjacent said drying spaces the fibrous web isguided over a plurality of guiding devices.
 4. The method according toclaim 3, said guiding devices being a plurality of individual turnrollers, said individual vertically aligned web guidance path sectionsprovided for said guidance of the fibrous web being defined by anarrangement of said plurality of individual turn rollers, saidindividual turn rollers being allocated to a drying space of saidplurality of drying spaces for transfer into and transfer out of arespectively an adjacent drying space of said plurality of dryingspaces.
 5. The method according to claim 1, wherein in said treatingstep both sides of the fibrous web are treated equally with said dryingmedium, at least in a region of one of said web guidance path sectionsinside an individual of said plurality of drying spaces.
 6. The methodaccording to claim 1, wherein in said treating step both sides of thefibrous web are treated differently with said drying medium, at least ina region of one of said web guidance path segments inside an individualof said plurality of drying spaces.
 7. The method according to claim 4,wherein in said step of treating the fibrous web includes the step ofcontrolling said treatment one of incrementally and infinitely, saidtreatment being uniform in an individual of said plurality of dryingspaces in a cross direction of the drying device and over an entireextension of a said individual of said plurality of drying spaces insaid vertical direction or said treatment of the fibrous web is profiledin at least one of a width direction and said vertical direction.
 8. Themethod according to claim 7, said step of controlling said treatment ofthe fibrous web is in at least one of a plurality of zones of one ofsaid plurality of blower devices.
 9. The method according to claim 8,further comprising the step of adjustably defining at least one of anoperational mode, a geometry of said individual blower device, a statevariable of said drying medium and a speed of the fibrous web using atleast one parameter, said at least one parameter including at least oneof: a dimensional geometry of an individual discharge opening; adischarge angle of said drying medium; a distance of said individualblower device from the fibrous web; a flow speed of said drying medium;a volume flow of said drying medium; a plurality of state variables ofsaid drying medium, said plurality of state variables includingtemperature and pressure; a throughput of said drying medium per timeunit; and a speed of the fibrous web.
 10. The method according to claim9, wherein said adjustably defining step includes controlling at leastone of said operational mode, said geometry of said individual blowerdevice, said state variable of said drying medium and said speed of thefibrous web.
 11. The method according to claim 10, wherein saidadjustably defining step includes regulating at least one of saidoperational mode, said geometry of said individual blower device, saidstate variable of said drying medium and said speed of the fibrous web.12. The method according to claim 11, wherein always said plurality ofdrying spaces arranged parallel to each other and extending in saidcross direction and said vertical direction of the drying device andsaid plurality of turn rollers coupling said plurality of drying spacesare combined into an individual group, a plurality of said individualgroups being arranged and configured such that an extension of said webguidance path sections progressing through said plurality of dryingspaces viewed in said vertical direction from an infeed into the dryingdevice to an outfeed of the drying device increases in size from a firstgroup of said plurality of individual groups to a subsequent group ofsaid plurality of individual groups.
 13. The method according to claim12, wherein said plurality of individual groups are arranged andconfigured such that said speed of the fibrous web an individual of saidplurality of groups is controlled separately.
 14. The method accordingto claim 3, further comprising the step of providing a drying mediumsupply system allocated to supply at least one individual of saidplurality of blower devices, said drying medium to be supplied to adrying space and said drying medium enriched with moisture from saiddrying space is led between two adjacent of said plurality of blowerdevices of one of said plurality of blower units or of different of saidplurality of blower units in a loop.
 15. The method according to claim14, said loop having a plurality of in-line heating devices.
 16. Themethod according to claim 15, said width of an individual of saidplurality of drying spaces is variably adjustable in a machinedirection.
 17. The method according to claim 1, further comprising thestep of severing the fibrous web one of consecutively and simultaneouslybetween individual said web guidance path segments if one of amalfunction and a web break occurs.
 18. A drying device for dryingfibrous webs, the drying device comprising: a plurality of blowerdevices arranged on a pair of opposing sides of a theoretical webguidance path and defining a drying space therebetween and arrangedextending in a cross direction of the drying device and extending in avertical direction of the drying device with a deviation of up to andincluding ±20°, said plurality of blower devices limiting a plurality ofsaid drying spaces progressing in said vertical direction, saidplurality of drying spaces progressing in said vertical direction beingarranged adjacent to each other in a machine direction to accommodate aplurality of guidance path sections, said plurality of blower devicesbeing configured for applying a drying medium onto the fibrous webguided in said plurality of drying spaces; and a plurality of turnrollers above and below an individual of said plurality of dryingspaces, two of said plurality of turn rollers being allocated to anindividual of said plurality of drying spaces for connection withadjacent said drying spaces defining said plurality of guidance pathsections, said two turn rollers being configured for transferring thefibrous web between two adjacent of said plurality of drying spaces. 19.The device according to claim 18, wherein individual of said pluralityof blower devices always arranged on a pair of opposing sides of anindividual web guidance path section represent a single blower unit,said individual of said plurality of blower devices being subdividedinto a plurality of blower zones in at least one of said cross directionof the drying device and said vertical direction of the drying device,the device further comprising a controller for at least one ofindividual and joint control of a plurality of said individual blowerzones.
 20. The device according to claim 19, said plurality of blowereach including a plurality of blow boxes arranged in said verticaldirection in a plurality of blower towers which are arranged extendingin said cross direction of the drying device, an individual of saidblower towers being supported on a frame.
 21. The device according toclaim 19, further comprising a drying medium supply system allocated toat least one of said plurality of blower devices.
 22. The deviceaccording to claim 21, further comprising a plurality of recirculatingblowers and a heating device, said plurality of recirculating blowersbeing arranged on a pair of opposing sides of said single blower unit,said plurality of recirculating blowers each having a suction sideconnected with one of said plurality of drying spaces and a pressureside connected with one of said plurality of blower devices of saidblower unit, forming a circulation stream, wherein said heating deviceis upstream from said connection of said pressure side with said oneblower device.
 23. The device according to claim 22, said recirculatingblowers being allocated to one of said plurality of blower devices andarranged in said vertical direction one above another and supported in ablower tower, said blower tower being formed one of separately and as acomponent of said frame.
 24. The device according to claim 21, saiddrying medium supply system including at least one fresh air supply andat least one exhaust air removal connected with at least one loop, saidfresh air supply and said exhaust air removal having no fluidicconnection with each other.
 25. The device according to claim 24, saidfresh air supply and said exhaust air removal being coupled thermallythrough a heat exchanger.
 26. The device according to claim 25, whereinalways a plurality of said drying spaces arranged parallel to each otherand extending in said cross direction and said vertical direction of thedrying devices and said plurality of turn rollers coupling said dryingspaces form a group, the device including at last two groups arrangedand configured such that an extension of said plurality of web guidancepath sections progressing through individual of said plurality of dryingspaces viewed in said vertical direction from an infeed into the dryingdevice to an outfeed from the drying device increases in size from afirst group of said at least two groups to a subsequent group of said atleast two groups.
 27. The device according to claim 26, furthercomprising a controller allocated to at least one of said at least twogroups for controlling a speed of the fibrous web.
 28. The deviceaccording to claim 27, said controller configured for controlling arotational speed of said plurality of turn rollers.
 29. The deviceaccording to claim 28, said controller configured for adjusting a widthof at least one individual of said plurality of drying spaces in saidmachine direction.
 30. The device according to claim 29, said singleblower unit being a plurality of blower units and the controllerincluding one of rotatable and pivoted mounting units for two adjacentlylocated of said plurality of blower devices of different of saidplurality of blower units, said mounting units including one ofrotatable and pivoted rocker arms on which said plurality of blowerdevices are flexibly hinged at a plurality of predetermined distances toa pivot point in a plurality of different mounting regions, said rockerarms including a force application surface for an adjusting device. 31.The device according to claim 30, wherein said plurality of rotatable orpivoting mounting units for a plurality of always adjacently arranged ofsaid plurality of blower devices are forcibly coupled in regard to theirrespective actuation.
 32. The device according to claim 18, furthercomprising a knock-off device configured for one of simultaneous andconsecutive movement between two of said plurality of drying spaces.